The average age of presidents has climbed over the past decade, up from 59.9 in 2006 to 61.7 in 2016, according to the data which comes from a survey of over 1,500 college and university presidents in the US.

Less than one-third of presidents are women and less than one-fifth are minorities.

Colleges seem to prioritize experience when selecting presidents, which skews the pool of candidates toward white men, hurting diversity efforts, according to the study.

While there has been growth for both women and minority groups, the progress has been slow, especially for the latter. In 2006, 23% of presidents were women; in 2016 that figure stood at 30%, an increase of seven percentage points.

Minority presidents represented 13.6% of college presidents in 2006; in 2016 that figure increased to 16.8%, an increase of 3.2 percentage points.

The representation of minority presidents looks even more stark when you take into consideration that many of those work at minority-serving institutions — like historically black colleges.

At some of the best schools in the US, the homogeneity of college presidents is on display.

Take Harvard University, for example. None of the presidents in the school's 380 years of existence has been a person of color.

Business Insider / Samantha Lee

In the 21st century, Harvard appointed its first female president to the helm. Drew Gilpin Faust has served as the president since 2007, though she recently announced she will step down in 2018.

Yale University, which is 315 years old, follows the same pattern.

Business Insider / Samantha Lee

Hanna Holborn Gray served as acting president at Yale from 1977-78 after Kingman Brewster became the US ambassador to Great Britain. Brewster chose Gray as his successor while Yale decided who would become the next president. She didn't receive an offer and Bartlett Giamatti become Yale's next-serving president.

And Princeton University, which is 270 years old, has also had one female president and no minority presidents.

Business Insider / Samantha Lee

Shirley Tilghman served as president from 2001 - 2013. She continues to teach molecular biology and public policy at the Ivy League school.

While progress is slow, there are some hopeful signals among college leaders.

Overwhelmingly, according to the survey, presidents seem to want to address the pipeline problem to the college presidency. Ninety percent believe it is important or very important to encourage faculty searches that yield a significant number of qualified minority candidates.